Gelled hydrocarbon fuels and process of preparing the same

ABSTRACT

A gelled hydrocarbon fuel containing more than 97 percent by volume hydrocarbon fuel and leaving less carbon deposits prepared by gelling the hydrocarbon fuel with a fatty acid diethanolamide, diethanolamine, a fatty acid triethanolamine ester, or triethanol amine and a small proportion of water.

United States Patent Iwama et al.

[ Apr. 30, 1974' GELLED HYDROCARBON FUELS AND PROCESS OF PREPARING THE SAME Inventors: Akira Iwama, Tokyo; Mitsuru Toyoguchi, Kanagawa; Motoo Kimura, Tokyo; Hiroyuki Ihara, Kanagawa, all of Japan Assignee: Mitsubishi Oil Co., Ltd., Tokyo,

Japan Filed: Dec. 2, 1971 Appl. No.: 204,320

Foreign Application Priority Data [56] References Cited UNITED STATES PATENTS 2,388,887 11/1945 Weissberger 44/? C X 3,049,498 8/1962 Sawyer 44/7 C X 3,012,966 12/1961 Copes et al. 44/7 A 3,148,958 12/1964 MOniCk 4417 A 3,459,608 8/1969 Ludolphy et al.... 149/46 X 3,505,374 4/1970 Monroe 44/7 C 3,586,490 6/1971 Karg 149/109 X 3,684,733 8/1972 Bannister, et al. 44/7 C Primary Examiner-Stephen .1. Lechert, Jr. Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn and Macpeak [57] ABSTRACT A gelled hydrocarbon fuel containing more than 97 percent by volume hydrocarbon fuel and leaving less carbon deposits prepared by gelling the hydrocarbon fuel with a fatty acid diethanolamide, diethanolamine, a fatty acid triethanolamine ester, or triethanol amine and a small proportion of water.

12 Claims, No Drawings GELLED HYDROCARBON FUELS AND PROCESS OF PREPARING THE SAME BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gelled hydrocarbon fuel having a high content of hydrocarbon fuel which does not flow out when a fuel tank is damaged or falls down by reducing the fluidity of the fuel without reducing the burning quality of the hydrocarbon fuel for use in a domestic heating means, a spark ignition type reciprocating engine, a diesel engine, a jet engine, a rocket motor, a boiler, or a furnace. The invention further relates to a method of preparing such a gelled hydrocarbon fuel. In particular, the present invention relates to a stable, gelled hydrocarbon fuel having a concentration of hydrocarbon fuel as high as 97-99.5 percent by volume, and also to a process of easily preparing such an excellent gelled hydrocarbon fuel.

2. Description of the Prior Art For conventionally gelling a hydrocarbon fuel it is necessary to use large amounts of surface active agents and water to improve the stability of the gelled hydrocarbon fuel. In this case, the surface active agents employed in the gelation usually contain, as impurities, inorganic materials such as sodium hydroxide which was used as a catalyst for the production of the surface active agents. Accordingly, a gelled hydrocarbon fuel prepared using conventional surface active agents contains hydrocarbons in an amount as low as 90-97 percent by volume, as well as a large amount of water and large amounts of high molecular weight surface active agents and impurities such as sodium hydroxide. Such a fuel has faults such as when the fuel is burned, the efficiency of combustion is low and the formation of carbon deposite is large, and thus there are various practical problems in the case of using such conventional gelled hydrocarbon fuels.

On the other hand, if the content of the hydrocarbon becomes higher than the aforesaid range in conventional gelled hydrocarbon fuels, the stability of the gelled hydrocarbon fuel is reduced and when the gelled hydrocarbon fuel is allowed to stand after being stirred, a rapid degradation phenomenon occurs.

Such a gelled hydrocarbon fuel, containing 90-97 percent by volume hydrocarbon fuel is difficult to control in rate of combustion and suffers from the growth of bacteria due to the large water content. Therefore, a stable gelled hydrocarbon fuel containing a reduced proportion of water has been desired.

SUMMARY OF THE INVENTION The inventors have discovered specific surface active agents capable of increasing the content of hydrocarbon fuel in a gelled hydrocarbon fuel to almost a critical amount of 97-99.5 percent by volume, preferably 98.5-99.4 percent by volume, and at the same time have discovered a process of improving the stability of 6 ume of water and at least one of the following four sur face active agents;

A. fatty acid diethanolamide of the formula ll crnci-non wherein R represents an alkyl group .having five to carbon atoms,

B. diethanoamino of the formula wherein R represents an alkyl group having five to 20 carbon atoms, and

D. triethanolamine of the formula CHZCHZOH NCH2CH2OH CH,CH2OH Moreover, according to the present invention, there is also provided a process of preparing such a gelled hydrocarbon fuel by mixing a definite amount of the surface active agent as mentioned above and water in an amount of 1.5-4.0 times the amount of the surface active agent, with stirring, and then slowly adding a hydrocarbon fuel to the mixture, with stirring, so that the mixture always maintains its emulsified or gelled state.

The gelledhydrocarbon fuel thus produced encounters less degradation because the gel-forming film of water and the surface active agent having contained therein the hydrocarbon fuel as the interior gel phase is strong due to the bonding force based on the chemical structure of the surface active agent used and to the fact that water and the surface active agent are uniformly well mixed. Therefore, the gelled hydrocarbon fuel is stable since the film is less broken at the surface of the gel brought into contact with air or vessels, and also components having a low boiling point and liable to be evaporated are contained in the gel-forming film, which controls the evaporation of these components. Therefore, the ignition point of the fuel is increased and the flame propagation rate is reduced, whereby the stability of the fuel is increased. Further, the rate of combustion is controlled.

DETAILED DESCRIPTION OF THE INVENTION The hydrocarbon fuel used in this invention includes petroleum hydrocarbon fuels having a boiling point range of 35550C.

In the case where a gelled hydrocarbon fuel having a low consistency for further reducing the fluidity of the gelled hydrocarbon fuel in accordance with the above purposes is desired, a gelled hydrocarbon fuel having a lower consistency than that of the abovedescribed gelled hydrocarbon fuel can be obtained by using a gel stabilizer. That is, at least one of the aforesaid four kinds of the surface active agents is mixed with an aqueous solution of a gel stabilizer in an amount of 1.5-4.0 times by volume the amount of the surface active agent and then the hydrocarbon fuel is added slowly to the mixture with stirring so that the mixture always maintains its emulsified or gelled state. Thus, a gelled hydrocarbon fuel having a hydrocarbon fuel content of more than 97 percent by volume and a low consistency can be obtained.

As illustrative aqueous solutions of gel stabilizers there are aqueous solution of gelatin, agar, a yolk, gum arabic, or an electrolytic high molecular weight compound such as a polycarboxylic acid and polyol and, if necessary, the warm aqueous solution of the above material.

When the gelled hydrocarbon fuel of this invention is burned in an evaporation type combustion device, such as a pot-type oilstove or wick-type oilstove, the surface active agent burns as the hydrocarbon fuel in the gelled fuel since the surface active agent contains carbon, hydrogen, oxygen, and a small proportion of nitrogen but does not contain non-volatile matter such as metallic components. In particular, because the gelled hydrocarbon fuel prepared by using a fatty acid diethanolamide or a fatty acid triethanolamine ester having a low carbon number is excellent in evaporating -property, the gelled hydrocarbon fuel has excellent combustibility as compared with one prepared using a surface active agent having a larger carbon atom number. For example, the gelled hydrocarbon fuel prepared using the fatty acid diethanolamide or the fatty acid triethanolamine ester having an alkyl group of five to nine carbon atoms included within the range of the carbon atom number of this invention give less carbon deposits when evaporated and burned, as compared with conventional gelled hydrocarbon fuel prepared using a nonionic surface active agent composed of a fatty acid having an alkyl group of l l-l7 carbon atoms, such as a polyoxyethylene stearic acid ester of polyoxyethylene sorbitan monolaurate. This is quite advantageous in handling evaporation type combustion devices, such as pot-type oilstoves or wicktype oilstoves after the combustion of the fuel.

The following examples are intended to illustrate the present invention but not to limit in any way.

EXAMPLE 1 Gelation of aircraft fuel JP-4:

To prepare a gel consisting of 0.3 parts by volume of an equimolar mixture of lauric acid diethanolamide and diethanolamine, 0.9 parts by volume of water, and 98.8 parts by volume of .lP-4 (ASTM Dist, boiling point range of 55-235C. ml. of the above surface active agents and 45 ml. of water were placed in a 500 ml. beaker and the mixture was stirred well by a rod.

Then, ml. ofJP-4 was first added to the mixture fol- 6 lowed by stirring until the mixture was completely emulsified or gelled, and thereafter the balance of the .lP-4 added. in this case, it should be noticed that the amount of JP-4 incrementally added each time until the adition was completed was not over about one-third of the amount of the emulsified or gelled mother liquid so that separation of JP-4 did not occur. When the total amount of the emulsified or gelled mother liquid was over 300 ml., the product was poured into a 5 liter beaker and then 4,700 ml. of JP-4 added slowly while stirring the system by means of a mixer at a rotation rate of 5003,000 rpm, whereby 5 liters of gelled JP-4 was obtained.

The gelled J P-4 obtained in the example was a translucent, stable, jelly-like gel, and when it was stored in a 5 liter polyethylene vessel for 60 days at 15C., no

degradation phenomenon occured. Also, when the flame propagation rate of the gelled J P-4 thus obtained was measured in a stainless steel vat l,000 mm in length, mm. in width, and 20 mm. in depth, the propagation rate was 5-l0 cm./sec., which is less than one-tenth of the flame propagation rate cm/scc., of

JP-4 before gelation.

Therefore, when the gelled JP-4 of this invention is used as an aircraft fuel, it shows excellent resistance against burning up and the danger of fire at an aircraft accident is reduced.

The chemical structure of lauric acid diethanolamide is as follows:

EXAMPLES 2-6 The gelation of .lP-4 as used in Example 1 was conducted employing the surface active agents and the mixing ratios shown in the following table according to the process of Example 1, and it was confirmed that gelled JP-4 having excellent stability was obtained in each case.

EXAMPLE 7 Gelation of kerosene as a fuel for domestic heating means:

To prepare a gelled kerosene consisting of 0.4 parts by volume of a mixture of 1.0 mol of capric acid diethanolamide* and 1.2 mols of diethanolamine, 0.9 parts by volume of water, and 98.7 parts by volume of kerosene (ASTM Dist. Boiling point range 155-245C), 12 ml. of the surface active agent mixture and 27 ml. of water were first placed in a 500 ml. beaker and the mixture was stirred vigorously with a rod to provide an emulsified or gelled mother liquid. The kerosene was further added successively to the emulsified or gelled mixture so that the incremental amounts thereof was not over one-fourth of the volume of the mother liquid until the total volume was about 300 ml. Then, the emulsified or gelled mother liquid was transfered to a 5 liter beaker and 2,700 ml. of the kerosene slowly added to the mixture, while stirring the system by means of a mixer at SOD-3,000 rpm., so that the system maintained its emulsified or gelled state to provide 3,000 ml. of the gelled kerosene.

As is clear from the above results, the amount of the carbon deposit of the sample of this invention was lessthan one-tenth that of the comparison sample.

EXAMPLES 8-10 The gelation of kerosene as used in Example 7 was conducted using the surface active agents and the mixing ratios shown in the following table as in Example 7,

and it was confirmed that gelled kerosene excellent in- Example Amount of Surface active agents and Water No. kerosene mixing ratios in vol% content in vol% vol% 8 98.7 caprylic acid diethanolamide 0.15 0.9 capric acid diethanol amide 0.15 diethanolamine 0.10

9 98.5 lauric acid diethanol amide 0.25 1.1 diethanolamine 0.15

10 98.5 caprylic acid triethanol amine ester 0.10 1.2 lauric acid diethanol amide 0.10 diethanolamine To confirm that the gelled kerosene thus obtained Sample The gelled kerosene The gelled kerosene prepared in the example prepared using the conventional surface active agent Carbon 1 1 g. 180 g. deposit in the pot )2 The chemical structure of capric acid diethanolamide is as follows:

O CH CH OH A gelled kerosene consisting of 1.5 percent by volume polyoxyethylene stearic acid ester, 3.0 percent volume water, and 95.5 percent by volume kerosene was used.

The chemical structure of polyoxyethylene stearic acid. ester is as follows:

EXAMPLE 1 l Gelation of gas oil:

To prepare gelled gas oil consisting of 0.5 parts by volume of a mixture of 1 mol of palmitic acid diethanolamide and 1.2 mols of diethanolamine, 2.0 parts by volume of water, and 97.5 parts by volume of gas oil (ASTM Dist. boiling point range of -350C.), 50 ml. of the surface active agent mixture and 200 ml. of water were added to a 12 liter vessel. The bottom of the vessel was connected to a pipe-line mixer by a polyvinyl chloride pipe having an inside diameter of 10 mm. and the vessel was further connected to the mixer by an other polyvinyl chloride pipe for circulating the contents of the vessel. While controlling the rotation a mixer in the range of SOD-2,000 rpm., 9,750 ml. of gas oil was slowly added to the vessel to provide 10 liters of gelled gas oil. When the gelled gas oil thus obtained was burned in a pressure spray-type hot-water boiler at a spray pressure higher than 7 kg./cm. it showed almost the same burning performance as that of the original gas oil. In the following table are shown the results of analysing the combustion gas and smoke by means of a Bacharach Smoke Meter.

EXAMPLES 12 AND 13 CH2CH2OH The gelation of gas oil as used in Example 12 was R-C-N conducted using the surface active agents and the mix- 3, \cHzcHzoH ing ratios shown in the following table according to the 5 PT f EX P and it WaS confirmed that 8 wherein R represents an alkyl group having five to nine gelled gas oil excellent in stability and burning performb n m ancc as Ob a ned in each C e- 3. The gelled hydrocarbon fuel as claimed in claim 1 wherein said surface active agent is an equimolar mixl0 ture of the fatty acid diethanolamide represented by the formula Example Amount Surface active agents Water No. of gas and mixing ratios in content oil vol% vol% in vol% (mcmou 12 98.0 caprylic acid 0.0l 1.55

diethanol-amide 1 R-( -N capric acid do. 0.02 lauric acid do. 0.20 O CH2CH2OH myristi c acid do. 0.06 g gg gg'i g 8-8; wherein R represents an alkyl group having five to diethanolamine 0.10 carbon atoms, and diethanolamine. l3 pa 20 4. The gelled hydrocarbon fuel as claimed in claim 1 triethanolamine ester I acid 0 4 wherein said surface active agent s an equlmo ar mixtri t a amin ester ture of the fatty acid tnethanolamme ester represented triethanolamine 0.2 y the formula What is claimed is: /CH2CH2OH l. A stable gelled hydrocarbon fuel consisting of RC-OCH2CH2N 97-995 ercent b volum f a roca n p y e o hyd rbo fuel and O CHZCHZOH 0.5-3.0 percent by volume of the sum of water and at least one of the following surface active agents;

a fatty acid diethanolamide of the formula wherein R represents an alkyl group having five to 20 carbon atoms, and triethanolamine.

5. The gelled hydrocarbon fuel as claimed in claim 1 /CH2CH2OH wherein the amount of water is 1.5-4.0 times by volume of the volume of the surface active agent.

6. The gelled hydrocarbon fuel as claimed in claim 1 wherein the sum of the amounts of the surface active agent and water is 0.6-1.5 percent by volume and the II o cn ca oa h i R represents an alkyl group having fi to 20 amount of said hydrocarbon fuel IS 98.5-99.4 percent carbon atoms, by volume. I I

B a di h l i f the f l 7. The gelled hydrocarbon fuel as clalmed m claim 1 wherein said hydrocarbon fuel is a petroleum hydrocar- CHZCHZOH bon having a boiling point range of 3S550C.

8. A process for the preparation of a stable gelled hy drocarbon fuel which comprises mixing at least one of CHZCHZQH the following surface active agents; W A. a fatty acid diethanolamide of the formula C. a fatty acid triethanolamine ester of the formula CHZCHQOH RCN cmcmou Ii 0 CH CH OH RCOCHCH2N H CHZCHZOH wherein R represents an alkyl group having five to 20 carbon atoms,

B. diethanolamine of the formula wherein R represents an alkyl group having five to 20 carbon atoms, and

D. triethanolamine of the formula HN CH CH Ol-l 6O CHZCHZOH NicHzcflzofl C. a fatty acid triethanolamine ester of the formula 2. The gelled hydrocarbon fuel as claimed in claim 1 wherein said surface active agent is the fatty acid diethanolamide represented by the formula 0 tlit-tH OH wherein R represents an alkyl group having five to carbon atoms, and

D. triethanolamine of the formula o CH2CH2OH wherein R represents an alkyl group having five to nine carbon atoms and diethanolamine.

10. The process as claimed in claim 8, wherein said surface active agent is an equimolar mixture of the fatty acid diethanolamide of the formula 3O CH CH OH 0 Cl-l CH Ol-l wherein R represents an alkyl group having five to 20 carbon atoms and diethanolamine.

11. A stable gelled hydrocarbon fuel consisting of 97-995 percent by volume of a hydrocarbon fuel,

0.53.0 percent by volume of the sum of water and at least one of the following surface active agents: A. a fatty acid diethanolamide of the formula (H CH OH R(N ll 0 (H (H,()H

wherein R represents an alkyl group having five to 20 carbon atoms,

B. a diethanolamine of the formula CH CH OH CH CH OH C. a fatty acid triethanolamine ester of the formula CHZC HZOH RiI-O-CH C H2N CH Cl-l Ol l,

wherein R represents an alkyl group having five to. 20

carbon atoms, and

D. triethanolamine of the formula and a gel stabilizer.

12. The gelled hydrocarbon fuel as claimed in claim 11 wherein said gel stabilizer is gelatine, agar, a yolk, gum arabic, or an electrolytic high molecular weight compound. 

2. The gelled hydrocarbon fuel as claimed in claim 1 wherein said surface active agent is the fatty acid diethanolamide represented by the formula
 3. The gelled hydrocarbon fuel as claimed in claim 1 wherein said surface active agent is an equimolar mixture of the fatty acid diethanolamide represented by the formula
 4. The gelled hydrocarbon fuel as claimed in claim 1 wherein said surface active agent is an equimolar mixture of the fatty acid triethanolamine ester represented by the formula
 5. The gelled hydrocarbon fuel as claimed in claim 1 wherein the amount of water is 1.5-4.0 times by volume of the volume of the surface active agent.
 6. The gelled hydrocarbon fuel as claimed in Claim 1 wherein the sum of the amounts of the surface active agent and water is 0.6-1.5 percent by volume and the amount of said hydrocarbon fuel is 98.5-99.4 percent by volume.
 7. The gelled hydrocarbon fuel as claimed in claim 1 wherein said hydrocarbon fuel is a petroleum hydrocarbon having a boiling point range of 35*-550*C.
 8. A process for the preparation of a stable gelled hydrocarbon fuel which comprises mixing at least one of the following surface active agents; A. a fatty acid diethanolamide of the formula
 9. The process as claimed in claim 8 wherein said surface active agent is an equimolar mixture of the fatty acid diethanolamide represented by the formula
 10. The process as claimed in claim 8, wherein said surface active agent is an equimolar mixture of the fatty acid diethanolamide of the formula
 11. A stable gelled hydrocarbon fuel consisting of 97-99.5 percent by volume of a hydrocarbon fuel, 0.5-3.0 percent by volume of the sum of water and at least one of the following surface active agents: A. a fatty acid diethanolamide of the formula
 12. The gelled hydrocarbon fuel as claimed in claim 11 wherein said gel stabilizer is gelatine, agar, a yolk, gum arabic, or an electrolytic high molecular weight compound. 